Female Mass Murderers: Major Cases and Motives

Of her seven victims, three were black, one was Chinese-American, one was Filipino, and one was Hispanic. Only Beverly Graham was white. Neighbors from the development where Graham lived reported that she and San Marco had argued while San Marco was residing there. 

Flowers for the victims,
Goleta, Caligornia.

By the end of the week, reporters for the Associated Press had learned from notes found in her New Mexico home that San Marco believed she was in danger from a conspiracy among workers at the Goleta processing plant.  She also left behind indications that she had a will. A check, made out to cash, was found that had the word "will" written on it. She had legally purchased the gun and ammunition from a pawn shop in New Mexico, and the requisite background check had turned up no problems.

San Marco reportedly also had issues with the Santa Barbara Police Department and a California medical facility, but apparently chose to vent her fear and anger at the processing plant.  If she meant to have someone inherit her home and money, that person's identity remains a mystery.

Criminologists called San Marco's rampage the worst workplace shooting by a woman in United States history.  Indeed, they were right.  There are few examples of female mass murderers of any kind, even including those who attempted to become one, but simply failed to take enough lives to meet the criteria.  In nearly every instance, whether they killed relatives, friends, or co-workers, they had a history of mental illness.  At no time did they exhibit the anger management issues of male mass murderers who simply had a vendetta and sought to harm as many people as they could.